The origin of the Akkadian šarru is rather uncertain, as its WS cognates are restricted to Ugr. and Hbr. only (see below).
May be related to Hbr. ŝəˁārā, səˁārā ‘storm’ and, perhaps, Arb. šiˁār- ‘thunder’ (Kogan 2015:96)
Cf. perhaps Gez. ŝāˀŝəˀa ‘to speak well, to speak clearly’